Herstellung und Charakterisierung von sauerstoffionenleitenden Dünnschichtmembranstrukturen

Betz, Michael

Dissertation / PhD Thesis/Book

Herstellung und Charakterisierung von sauerstoffionenleitenden Dünnschichtmembranstrukturen

Betz, M. (Corresponding author)FZJ*

2010
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-89336-618-7

Jülich : Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag, Schriften des Forschungszentrums Jülich : Energie & Umwelt / Energy & Environment 61, 61 S. (2010) = Ruhr-Universität Bochum

Please use a persistent id in citations: http://hdl.handle.net/2128/3727

Abstract: In power plants using Oxyfuel technology, fossil fuels are combusted with pure oxygen. This leads to carbon dioxide of high purity, which is necessary for its transport and storage. Oxygen separation by means of perovskitic membranes have great potential to decrease the efficiency losses caused by the allocation of the enormous amounts of oxygen. The aim of this work is the preparation and characterisation of thin film membranes on porous substrates and the analysis of their oxygen permeation properties. Therefore the material system A$_{0,68}$Sr$_{0,3}$Fe$_{0,8}$Co$_{0,2}$O$_{3−\delta}$ (A68SFC) was analysed, where the A-site was substituted with Lanthanides (La, Pr, Nd, Eu, Sm, Gd, Dy, Er) or alkaline earth metals (Ba, Ca). After an extensive characterisation, the selection was reduced to the substitutions with La, Pr and Nd. Other compounds could not meet the demands with regard to phase purity, chemical stability or extension behaviour. All analyses were conducted in comparison to Ba$_{0,5}$Sr$_{0,5}$Co$_{0,8}$Fe$_{0,2}$O$_{3−\delta}$ (BSCF) which is known to exhibit higher permeation rates, but is more sensitive to stability issues. The dependency of permeation rates on membrane thickness or oxygen partial pressures on both membrane surfaces is discussed by means of permeation measurements conducted on bulk BSCF membranes. These cannot be described completely by the Wagner equation. This is due to changes of the driving force originating from influences of the surface reaction kinetics and concentration polarisation on the membrane surface, which are not considered. Porous substrates for asymmetric membranes were manufactured by tape casting and warm pressing. The application of the functional layer was performed via screen printing. Permeation measurements show that the asymmetric structures exhibit higher permeation rates in comparison to bulk membranes with L=1 mm. The moderate increase can be attributed to the low gas permeability of the substrates used.

Classification: